140 BEITISH OAK GALLS. 



much as 10-12 mins. can be obtained, by pressure, 

 from a large gall. The disagreeable bitterness of the 

 fluid makes the gall exceedingly unpleasant to the 

 human palate. 



This gall is exceedingl}^ pretty and attractive. The 

 English name of " pink wax " is eminently suitable. 

 It bears some resemblance to Spathegaster haccarum, 

 but while that species is almost tasteless, this species 

 is very astringent. 



In size, even although mature, it varies greatly ; 

 some species being not more than 12 mm. in girth, 

 others attaining 45-50 mm. in girth. 



In shape also there is considerable variation, some 

 being oval, ovoid, and spherical. The prevailing form 

 is globular, slightly depressed where attached, and 

 occasionally at the opposite pole also. The w^alls are 

 very thick ; the larval cavity very small. 



The mode of growth is such that the gall appears 

 to be sessile, a deception increased when it is sur- 

 rounded with moss, lichen, ivy, or very small twigs. 

 Its origin is from a bud, not from the bark. It is 

 always attached by a peduncle, which although small, 

 delicate, and easily severed, retains the gall until 

 mature, or the tenant has emerged, and even when it 

 has shrivelled, and become inconspicuous. 



At intervals of several years they are particularly 

 abundant, many hundreds appearing on the trunks of 

 old trees. They are found most frequently low down 

 the bole of the tree ; they also affect small twigs in the 

 same lowly position, especially when lightly covered 

 with loose earth and leaves ; they may also be sought 

 on twigs along the bottom of a hedge ; but, the best 

 place of all is the stump of an old pollard oak in a 

 wood or lane. 



